Superstructures of wet inactive chromatin and the chromosome surface

Superpacking of chromatin and the surface features of metaphase chromosomes have been studied by SiO replication of wet, unstained, and unfixed specimens in an exceedingly thin (≤ 1 nm) aqueous layer, keeping them wet. Hydrophilic Formvar substrates allow controlled thinning of the aqueous layer covering the wet specimens. Whole mounts of chromatin and chromosomes were prepared by applying a microsurface spreading method to swollen nuclei and mitotic cells at metaphase. The highest level of nucleosome folding of the inactive chromatin in chicken erythrocytes and rat liver nuclei is basically a second-order superhelical organization (width 150–200 nm, pitch distance 50–150 nm) of the elementary nucleosome filament. In unfavorable environments (as determined by ionic agents, fixative, and dehydrating agents) this superstructure collapses into chains of superbeads and beads. Formalin (10%) apparently attacks at discrete sites of chromatin, which are then separated into superbeads. The latter consist of 4–6 nucleosomes and seemingly correspond to successive turns of an original solenoidal coil (width 30–35 nm), which forms the superhelical organization. When this organization is unfolded, eg, in 1–2 mM EDTA, DNAse-sensitive filaments (diameter 1.7 nm) are seen to be wrapped around the nucleosomes. The wet chromosomes in each metaphase spread are held to each other by smooth microtubular fibers, 20–30 nm in diameter. Before they enter into a chromsome, these fibers branch into 9–13 protofilaments, each 5 nm wide. The chromosome surface contains a dense distribution of subunits about 10–25 nm in diameter. This size distribution corresponds to that of nucleosomes and their superbeads. Distinct from this beaded chromosome surface are several smooth, 23–30-nm-diameter fibers, which are longitudinal at the centromere and seem to continue into the chromatid structure. The surface replicas of dried chromosomes do not show these features, which are revealed only in wet chromosomes.     

Solar UV radiation modulates daily production and DNA damage of marine bacterioplankton from a productive upwelling zone (36°S), Chile

In upwelling ecosystems, such as the Humboldt Current system (HCS) off Concepción, the effects of solar radiation on bacterioplankton incorporation rates have been related to previous light acclimation and responses to irradiance. In this paper, we study the daily effect of Photosynthetic Active Radiation (PAR, 400-700 nm) and ultraviolet radiation UVR (280-400 nm) on bacterial secondary production (BSP). We also considered the DNA damage-repair response to solar radiation stress by the induction of cyclobutane pyrimidine dimers (CPDs). Experiments were conducted with natural bacterioplankton assemblages (0.2-0.7 μm) collected off Concepción (36°S), during the austral Spring, October-November, 2004. Surface (0.5 m) and subsurface (80 m) bacterioplankton samples were exposed to different solar radiation treatments for 5-20 h. BSP was estimated by ¹⁴C-leucine and ³H-thymidine incorporation at several time intervals, whereas CPDs accumulation was assessed using immunoassay techniques. During high irradiance periods, BSP was mainly affected by PAR in both surface and subsurface assemblages and, to a lesser, but significant (Tukey < 0.05) extent, by UV-A (320-400 nm) and UV-B (280-320 nm) radiation. Maximum inhibition of BSP in surface waters was 78%; growth rates (μ) and bacterial growth efficiency (BGE) were also low (78% and 66% respectively). Subsurface water assemblages, on the contrary, showed a ∼ 25 fold enhancement of BSP, μ, and BGE. Both types of assemblages had a rapid CPDs accumulation (maximum 60 CPDs Mb^− 1) during high irradiance periods. Recovery of BSP inhibition and DNA damage in surface bacteria was total after sunset and after the night incubation period, resembling pre-exposure levels. Despite subsurface BSP enhancement during day-night exposure, residual DNA damage was detected at the end of the experiment (20 CPDs Mb^− 1) suggesting a chronic DNA damage. Our results represent the worst case scenario (i.e., assemblages receiving surface irradiances as may occur in this upwelling zone) and indicate that surface and subsurface bacterial assemblages in the HCS are both highly sensitive to solar irradiance. However, they showed different responses, with surface bacteria having more effective photorepair mechanisms, and sustaining higher BSP than subsurface assemblages.     

The structure of the nucleosome core particle of chromatin in chicken erythrocytes visualized by using atomic force microscopy

The structure of the nuclosome core particle of chromatin in chicken erythrocytes has been examined by using AFM.The 146 bp of DNA wrapped twice around the core histone octamer are clearly visualized.Both the ends of entry/exit of linker DNA are also demonstrated.The dimension of the nucleosome core particles is - 1-4 nm in height and - 13-22 nm in width.In addition,superbeads (width of - 48-57 nm,height of - 2-3 nm )are occasionally revealed,two turns of DNA around the core particles are also detected.     

Hydrological connectivity structures concordant plant and animal assemblages according to niche rather than dispersal processes

1. Understanding the processes that structure community assembly across landscapes is fundamental to ecology and for predicting and managing the consequences of anthropogenically induced changes to ecosystems. 2. We assessed the community similarity of fish, macroinvertebrate and vegetation communities against geographic distances ranging from 4 to 480 km (i.e. distance–decay relationships) to determine the balance between local environmental factors and regional dispersal processes, and thus whether species‐sorting (niche processes) or dispersal limitation (neutral processes) was more important in structuring these assemblages in Australia’s wet‐dry tropics. We investigated whether the balance between niche and dispersal processes depended on the degree of hydrological connectivity, predicting that dispersal processes would be more important at connected sites, and also whether there was spatial concordance among these three assemblage types. 3. There was significant but weak spatial concordance among the study communities, suggesting limited potential for surrogacy among them. Distance–decay in community similarity was not observed for any study assemblage at perennial sites, suggesting dispersal was not limiting and assemblages were structured more strongly by local niche processes at these connected sites. At intermittent sites, weak distance–decay relationships for each assemblage type were confounded by significant relationships with environmental dissimilarity, suggesting that dispersal limitation contributed, albeit weakly, to niche processes in structuring our three study assemblages at disconnected sites. 4. Two environmental factors, flow regime and channel width, explained significant proportions of variation in all three assemblages, potentially contributing to the observed spatial concordance between them and representing local environmental gradients along which these communities re‐assemble after the wet season, according to niche rather than dispersal processes.     

In situ Responses of Phytoplankton from the Subtropical Lake La Angostura (Tucumán, Argentina) in Relation to Solar Ultraviolet Radiation Exposure and Mixing Conditions

In situ experiments were conducted at various depths in the water column to determine the effects of solar ultraviolet radiation (UVR, 280–400 nm) on photosynthesis of natural phytoplankton assemblages from the subtropical Lake La Angostura (Argentina, 26°45′ S; 65°37° W, 1980 m asl.). Water samples were taken daily and incubated under three radiation treatments: (a) Samples exposed to UVR + Photosynthetic Available Radiation (PAR) – PAB treatment (280–700 nm); (b) Samples exposed to ultraviolet-A radiation (UV-A) + PAR – PA treatment (320–700 nm), and, (c) Samples exposed to PAR only – P treatment (400–700 nm). Additionally, depth profiles were done to determine different physical (i.e., temperature and underwater radiation field) and biological characteristics of the water column – photosynthetic pigments, UV-absorbing compounds, cell concentration, deoxyribonucleic acid (DNA) and cyclobutane pyrimidine dimers (CPDs). The effects of UVR on natural phytoplankton assemblages were significant only in the first 50 cm of the water column, causing a decrease in photosynthetic rates of 36 and 20% due to UV-A and ultraviolet-B radiation (UV-B), respectively; below this depth, however, there were no significant differences between radiation treatments. Concentration of CPDs per mega base of DNA in natural phytoplankton was low, <27 CPDs MB⁻¹ between 0 and 4 m. Data on net DNA damage, together with that on mixing conditions of the water column, suggest that mixing can favour phytoplankton by allowing cells to be transported to depths where active repair can take place. This mechanism to reduce UVR-induced DNA damage would be of great advantage for these assemblages dominated by small cyanobacteria and chlorophytes where UV-absorbing compounds that could act as sunscreens are virtually absent.     

Wavelength dependence of inactivation and membrane damage to Saccharomyces cerevisiae cells by monochromatic synchrotron vacuum-uv radiation (145-190 nm)

Using an electron storage ring as a source of radiation, the wavelength dependence of inactivation and membrane damage in yeast cells (Saccharomyces cerevisiae) was investigated in the range from 145 to 254 nm, with special reference to the effects of vacuum-uv radiation. The cells were irradiated on a Millipore filter in a moist chamber filled with water vapor (deoxygenated) at saturation pressure. Fluence-survival curves taken at 5-nm intervals were generally sigmoidal. Action spectra of the two types of effects were nearly identical in shape. The maximum occurred in both spectra at 160 nm, decreasing sharply toward 180 nm. The spectra remarkably resembled the calculated absorption spectrum of (liquid) water in the range from 145 to 170 nm; the spectra had no similarity at all to the absorption spectra of DNA, proteins, or lipids. These data support the theory that inactivation of wet cells by vacuum-uv radiation may be attributable to damage in the cell membrane initiated by the absorption of water molecules. Above 210 nm the spectrum for inactivation paralleled the absorption of DNA. Genetic changes (induction of gene conversion) were also observed above 210 nm. Photoreversion for the induced convertants was detectable only above 220 nm. These characteristics are consistent with the expectation that above 210 nm the site of major lethal damage shifts to DNA.     

Indicators of Diptera diversity in wet grassland habitats are influenced by environmental variability,scale of observation,and habitat type

In low intensity agri-ecosystems such as wet grassland habitats, the inclusion of invertebrates in conservation assessments and monitoring is usually limited to charismatic groups such as bees or butterflies. However, wet grasslands support a wide range of inveterate groups, some of which may exhibit limited movement not generally represented by more mobile groups such as those typically examined. The use of surrogate species which exemplify broader invertebrate diversity has been suggested as a possible means of including these overlooked invertebrates (such as Diptera) in conservation planning within these habitats. Based on collections made by Malaise trap, we utilized two families of Diptera (Sciomyzidae and Syrphidae) as indicators of a wider range of dipteran diversity (nine Diptera families identified to parataxonomic unit level [PUs]) in wet grassland habitats. We examined the role of environmental variability, spatial scale, and habitat type on patterns of cross-taxon congruence for all three assemblages. Both environmental correlation and community congruence were significantly stronger among assemblages when examined at low spatial scales, highlighting the need to examine dipteran groups at scales untypical of current agri-environmental assessments; namely field and farm level. Furthermore, when wet grasslands were differentiated into two habitat categories (sedge and rush dominated grasslands), the significance of the community congruence increased markedly. This correlation was particularly strong between Sciomyzidae and PUs which demonstrated similar differentiation based on habitat type, implying that assemblages which exhibit comparable ecological partitioning are more likely to be useful surrogates of one another. Correlations between richness, abundance and Shannon’s diversity were highly variable among groups, suggesting compositional analysis as the most appropriate examination of dipteran diversity for surrogacy studies. The results indicate that cross-assemblage congruence of Diptera is influenced by similarity of response to environmental variability, scale of observation, and examination of assemblages differentiated into appropriate habitat categories. The results illustrate the need to investigate invertebrate biodiversity surrogates at scales appropriate to the indicator groups and examine congruence among assemblages within specific habitat categories. Such an approach has the potential to maximise gamma diversity in areas where wet grasslands are under threat of intensification or abandonment.     

Effectiveness of incorporation of spermine-condensed viral DNA into liposomes. Interaction of liposomes with cells

DNA from bacteriophage lambda or monkey adenovirus type 7 have been condensed with spermine and included into three types of liposomes: ethereal, obtained by inverted phases technique and by Ca++ fusion. Compact DNA form presents a tor with 100 nm external diameter and 430 nm width. It can be included into 100 nm or larger liposomes. Total preparation contains 15-18% of the required liposomes. Liposomal fractions with included DNA were separated from empty liposomes by step gradient of ficoll 400. Liposomal fraction having included DNA contains 15-18% of common lipid. Liposomal interaction with monkey cell cultures has been studied.     

Spatial-temporal distribution of preimaginal blackflies in Neotropical streams

The current study investigates the spatial-temporal distribution of preimaginal blackflies in three a priori established, adjacent areas of Brazil and Venezuela. First we tested the hypothesis that the distribution of individual simuliid species, over two geographic scales, were predictable on the basis of several habitat parameters. Secondly, we determined if local species assemblages remain constant over two spatial axes, i.e., were species assemblages predictable within and between defined regions. Finally we compared the species assemblage between Venezuelan streams sampled in both the wet (October) and dry (February) seasons. As stream conditions changed across a north–south gradient, so did the occurrence of the most common species. This change in species composition from upland to lowland areas is consistent with the patterns of faunal change seen in North American simuliid assemblages. Discriminant Function Analysis showed a strong association between regional demarcations and stream site conditions. These results were paralleled by the strong correspondence between species assemblages and these regions. Thus each region presented both distinct stream environments and species assemblages. Monte Carlo analysis suggests that some if not all species are not only present in both the wet and dry season but that they are continuing to use the same stream sites. Three broad contingent rules for blackfly species assemblages in new world streams are put forward; (i) the ubiquitous nature of simuliids; (ii) species often distribute themselves along an axis of stream size and; (iii) there is a strong and consistent correspondence between regional characteristics of streams and the species assemblage.     

Biomolecular recognition in DNA tagged CdSe nanowires

DNA template driven CdSe nanobeads (NBs) and nanowires (NWs) have been synthesized by an electrodeposition technique. The synthesis protocol has yielded randomly oriented cubic CdSe NBs with mean size 3.0 nm in presence of single stranded DNA, poly G(30). Monocrystalline cubic CdSe NWs of width 4.0 nm with string-like morphology have been achieved when synthesized in presence of both poly G(30) and its conjugate, poly C(30). Optical absorption of CdSe NBs show a blue shift of 0.8 eV and long wavelength tailing where as NWs show steep increase of absorption in shorter wavelength regime accompanied by a further blue shift. DNA tags to the NBs or NWs have been confirmed from Fourier transform infrared spectroscopy measurements. Biomolecular recognition with CdSe NWs have been established by photoluminescence measurements.     

Environmental variability drives phytoplankton assemblage persistence in a subtropical reservoir

Temporal changes of assemblages may result from environmental variability and reflect seasonal dynamics of their ecosystem. In the subtropics, the hydrological regime is usually characterized by well‐defined wet and dry seasons, regulating discharge and influencing a series of environmental variables that affect phytoplankton persistence. Therefore, we may expect that dry seasons are environmentally more stable than wet seasons. We analysed interannual phytoplankton assemblage variability (or, inversely, persistence) in a subtropical reservoir sampled every austral summer and winter during 5 years. We tested (i) if phytoplankton assemblage structure differed between the dry (summer) and wet (winter) seasons; (ii) if assemblage persistence differed between the seasons; (iii) if assemblage persistence was related to environmental stability; and (iv) if assemblage dissimilarity increased over time. Phytoplankton assemblages differed between the summer and winter seasons. Winter indicator species were mostly Bacillariophyceae or Cryptophyceae, whereas Cyanophyceae and Chlorophyceae taxa were more frequent and abundant in summer. Assemblages in the dry season were more persistent among years than those occurring during rainy periods. Similarly, environmental variability tended to be lower among dry than among rainy seasons. The relation between the phytoplankton temporal cycle and the temporal patterns of environmental variability supports our prediction that high environmental stability results in more persistent assemblages. Assemblage dissimilarity increased as sampling years were farther apart, for both seasons. Additionally, assemblages in the rainy periods showed a more pronounced increase in dissimilarity, as their changes among years were less predictable. We found a clear temporal pattern and an increased dissimilarity over time in the phytoplankton assemblage structure. Unravelling these temporal patterns may improve our understanding of phytoplankton temporal dynamics, and may have implications for management and monitoring programs. High dissimilarity of assemblages among years, particularly among rainy periods, can obscure human impacts, and monitoring programs should take this into account.     

Diversity and biogeography of bacterial assemblages in surface sediments across the San Pedro Basin, Southern California Borderlands

Sediment bacteria play important roles in the biogeochemistry of ocean sediments; however, factors influencing assemblage composition have not been extensively studied. We examined extractable sediment bacterial abundance, the composition of bacterial assemblages using a high-throughput molecular fingerprinting approach, and several sediment biogeochemical parameters (organic matter content and alkaline phosphatase activity), along a 35 km transect from Point Fermin, Southern California, to Santa Catalina Island, across the approximately 900-m-deep San Pedro Basin. Automated rRNA intergenic spacer analysis (ARISA) demonstrated that in two spatially isolated shallow (approximately < 60 m, on opposite sides of the channel) sediment environments, assemblages were more similar to each other than to deeper communities. Distinct communities existed in deeper and shallower sediments, and stations within the deep basin over 2 km apart contained remarkably similar assemblage fingerprints. The relative contribution to total amplified DNA fluorescence of operational taxonomic units (OTUs) was significantly correlated to that of other OTUs in few comparisons (2.7% of total), i.e. few bacterial types were found together or apart consistently. The relative proportions within assemblages of only a few OTU were significantly correlated to measured physicochemical parameters (organic matter content and wet/dry weight ratio of sediments) or enzyme (alkaline phosphatase) activities. A low percentage of shared OTU between shallow and deep sediments, and the presence of similar, but spatially isolated assemblages suggests that bacterial OTU may be widely dispersed over scales of a few kilometres, but that environmental conditions select for particular assemblages.     

Photo and thermoluminescence of KMgSO4F: Ce and :Mn phosphors

KMgSO₄F:Ce and KMgSO₄F:Mn phosphors were prepared by a wet chemical method and studied for their photoluminescence (PL) and thermoluminescence (TL) characteristics. PL emission of KMgSO₄F:Ce peaked at around 440 nm for the excitation at 377 nm due to 5d → 4f transition, while KMgSO₄F:Mn had a peak at 540 nm for an excitation at 363 nm and 247 nm due to ⁴T_1g → ⁶A_1g transition. The phosphors also showed good thermoluminescence characteristics when they were exposed to γ‐rays at a 5 Gy dose at the rate of 0.36 kGyh^?1. KMgSO₄F:Ce exhibited a single thermoluminescence (TL) peak at around 167 °C and KMgSO₄F:Mn also exhibited a single TL peak at around 177 °C. Possible trapping parameters such as order of kinetics (b), the geometrical factor (μ_g), the frequency factor (s) and the activation energy were also evaluated by Chen's half width method. This article discusses fundamental PL and TL characteristics in inorganic fluoride material activated by Ce³⁺ and Mn²⁺ ions and prepared by a wet chemical method. Copyright © 2014 John Wiley & Sons, Ltd.     

SEASONALITY OF MARABOU STORKS LEPTOPTILOS CRUMENIFERUS IN EASTERN AFRICA

Nesting by Marabou Storks in eastern Africa is seasonal, and so are assemblages of non-breeding birds at places with a regular supply of food. In Uganda, where temperatures and day-length are almost constant, Marabous have nested at about the same time each year, despite considerable variations in rainfall from year to year. However, rainfall can have a modifying effect, delaying egg-laying by up to a few weeks. The timing of egg-laying varied regionally throughout eastern Africa, but in general nesting began during a dry season and continued into the next wet season. In drier areas the timing of nesting was more complex. Regional variations in the nesting season, and in the sizes of feeding assemblages, are consistent with north-south movements of individual Marabous to or across the equator, enabling them to avoid the late wet season and early dry season. These are times when the supply of natural foods is likely to be least. Figure 6 summarizes the data and indicates probable movements. In the wetter areas the main northwards movement is in October-November, returning four to six months later. In driet areas the timing is almost reversed.     

Seasonal differences and response to a tropical storm reflected in diatom assemblage changes in a southwest Florida watershed

Because estuaries are dynamic on many temporal scales, it is difficult to differentiate long-term shifts from those resulting from erratic pulse events like severe storms. Diatoms are abundant and diverse in estuaries, and may characterize these dynamics across relevant time scales. The climate of south Florida is subtropical, with dry winters and wet summers that may also harbor tropical storms and cyclones. We investigated whether these repeated seasonal drivers of change in estuaries differ from the influence of tropical cyclones on planktonic and benthic diatom assemblages. Diatom assemblages and environmental parameters were measured in the Charlotte Harbor watershed of southwest Florida to identify differences between the wet and dry seasons and changes that occurred following Tropical Storm Debby in 2012. Indicator taxa that were significantly affiliated with each season and post-storm conditions were identified. Diatom assemblages across the watershed were similar in wet and dry seasons, but differences increased following the tropical storm. The reduction in community dispersion following the storm was pronounced in each of the major drainages of the estuary. There were spatially-distinct responses of diatoms to environmental changes driven by the storm. These results suggest that past storm activity could be detected using diatoms preserved in estuarine sediments using both single indicator-species as well as community approaches.     

Atomic force microscopy of long and short double-stranded, single-stranded and triple-stranded nucleic acids.

Atomic force microscopy (AFM, also called scanning force microscopy) is proving to be a useful technique for imaging DNA. Thus it is important to push the limits of AFM imaging in order to explore both what types of DNA can be reliably imaged and identified and also what substrates and methods of sample preparation are suitable. The following advances in AFM of DNA are presented here. (i) DNA molecules as short as 25 bases can be seen by AFM. The short single-stranded DNAs imaged here (25 and 50 bases long) appeared globular in the AFM, perhaps because they are all capable of intramolecular base pairing and because the DNAs were in a Mg(ll) buffer, which facilitates intramolecular cross-bridging. (ii) AFM images in air of short double-stranded DNA molecules, 100-200 bp, gave lengths consistent with A-DNA. (iii) AFM images of poly (A) show both short bent lumpy molecules with an apparent persistence length of 40 nm and long straight molecules with an apparent persistence length of 600 nm. For comparison, the apparent persistence length for double-stranded DNA from phX-174 under the same conditions was 80 nm. (iv) Structures believed to be triple- stranded DNA were seen in samples of poly(dA.poly(dT) and poly (dG).poly(dC). These structures were twice as high as double-stranded DNA and the same width. (v) Entire molecules of lambda DNA, approx. 16 micron long, were imaged clearly in overlapping scans. (vi) Plasmid DNA was imaged on oxidized silicon, although less clearly than on mica.     

Declining diversity and abundance of High Arctic fly assemblages over two decades of rapid climate warming

Insects are particularly vulnerable to rapid environmental changes, which are disproportionally affecting high latitudes. Increased temperature could influence insect species differentially and reshape assemblages over time. We quantified temporal assemblage turnover of Arctic Diptera (flies) in the Muscidae, one of the most diverse and abundant families of Arctic insects, using time series data from Zackenberg, north‐east Greenland. We measured temporal patterns of abundance, diversity, and composition of muscid assemblages in wet fen, mesic and arid heath habitats from yearly collections spanning 1996–2014 and tested their relationship to climate. A total of 18 385 individuals representing 16 species of muscid flies were identified. A significant decrease of 80% of total muscid abundance was observed during the study period. Species richness declined in each habitat type but this trend was not significant across habitats. The number of common and abundant species also decreased significantly over time across habitats revealing a temporal modification of species evenness. Significant temporal changes in composition observed in the wet fen and across habitats were mainly driven by a change in relative abundance of certain species rather than by species replacement. Shift in composition in each habitat and decline in muscid abundance across habitats were associated with summer temperature, which has significantly increased over the study period. However, relationships between temperature and muscid abundance at the species level were noticeable for a few species only. Significant directional change in composition was documented in the wet fen but no biotic homogenization across habitats was observed. As one of the few studies of species‐level changes in abundance, diversity and composition of an insect taxon in the Arctic over the past two decades, our study shows that habitat types may modulate insect species responses to recent climate change and that contrasting species responses can alter species assemblages within a few decades.     

Influence of water chemistry and environmental degradation on macroinvertebrate assemblages in a river basin in south-east Brazil

Benthic macroinvertebrate assemblages, water chemistry variables and environmental degradation were investigated in an Atlantic Forest region in Brazil. Seven sites of the Guapimirim river basin were studied during three sampling periods based on the rain regime: end of wet season (May 1998), dry season (August 1998), and wet season (January 1999). Four substrates were collected at each site: sand, stony substrates, litter in pool areas and litter in riffle areas. Relationships between macroinvertebrate assemblages, water chemistry variables and environmental degradation were examined using canonical correspondence analysis (CCA). According to CCA, concentrations of dissolved oxygen and chloride, and the environmental degradation, measured by the Riparian Channel Environment index, exhibited the strongest relationship to macroinvertebrate assemblages. Overall, the loss of community diversity measured by the Shannon Index along the degradation gradient was observed. Some taxa were shown to be sensitive to water pollution, especially among Plecoptera, Trichoptera, Coleoptera and some Ephemeroptera, while others such as Simuliidae, Odonata and molluscs were tolerant to moderate levels of pollutants. The Chironomidae were the only group tolerant to a high level of pollutants and degradation.     

Indicating assemblage vulnerability and resilience in the face of climate change by means of adult ground beetle length–weight allometry over elevation strata in Tenerife (Canary Islands)

Adaptive trade-offs in length–weight allometry might reduce vulnerability under climate change of adult ground beetle (Col., Carabidae) assemblages in their original elevation stratum on Tenerife. In particular this study shows that the predictive values for simple log-linear regression parameters were high in all strata and also the F-tests were statistically significant (p < 0.0001). Ground beetle assemblage on upper stratum had smaller coefficients and higher intercepts than did lower ones, indicating that the ground-beetle assemblages may be trading off higher powers for higher resilience via water and thermal efficiency in the face of environmental warming, in opposition to strategies adopted in cool and wet climates. Adults of ground beetle assemblages from warm and dry lower strata might have to be heftier, with encapsulation of bodies and heavily sclerotized exoskeleton, than those from cloudy, cool and wet strata; the latter group, freed from this constraint, would thus be characterized by more elongated, thinner and softer-bodied species. The outlined methodology could become a useful tool for the vulnerability and resilience assessment of natural assemblages, and could theoretically be applied to any latitudinal and altitudinal assemblage.